Hi JADS,
Please refer SAP note
1676665 - Setting up Microsoft SQL Server 2012
683447 - SAP Tools for MS SQL Server
Please check SAP Product compatibility as described in above notes as well as PAM. Post this you may plan the in-place upgrade to MSSQL 2012.
Refer to a blog on in-place upgrade as below
Windows 2012 R2 In-Place Upgrade: SQL Configuration Manager Disappears
Hope this helps.
Regards,
Deepak Kori